RONALD KOEMAN has questioned whether his players have the mentality to adopt the aggressive approach which is central to how he wants Everton to perform.

The Everton manager highlighted his exacting standards by pouring over last weekend's defeat to Bournemouth and focusing on what he believes is his side's inability to press the ball properly during a blunt inquest.

Everton have spent the week working on their approach in training ahead of tonight's showdown with Crystal Palace but Koeman claimed the tactic was a "big problem" for some in his squad.

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Ronald Koeman has questioned his Everton players' inability to press the ball

"For some players it's difficult," he said. "If they are used to not pressing then it's difficult for some players. For some it's a big problem because they don't know what to do.

"So some will change their attitude and you wait, and finally you make up your mind yes, and no. It's a mental aspect not fitness. It is about attitude.

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"That was the attention in the sessions and we see will if we do it better than we did last week." Koeman has previously told his strikers they must work harder and his criticism comes with the 1-0 defeat at Bournemouth being the club's first league reverse of an otherwise positive start to the season.

"Sometimes it's difficult because our striker(s) is not used to pressing how we tried to press the opponent and it takes time. They found it difficult to do it in the way we want," said Koeman.

"I wasn't thinking that everything was done after the four wins but we gave more attention to how we need to do pressing because we have to improve in that area."